• 대한기계학회논문집B
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• 제39권4호
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• pp.371-378
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• 2015

전기자동차 레인지 익스텐더는 소형 엔진으로 구동되는 발전기 시스템(초소형 파워팩)으로서 자동차 운행 중 지속 충전을 통하여 운전 거리 및 시간을 연장한다. 기존 가솔린 엔진 파워팩은 복잡한 구조와 낮은 에너지 밀도로 인하여 고출력 소형 시스템 구현에 한계가 있다. 반면, 가스터빈 파워팩은 출력밀도가 매우 높고 고속화를 통해 시스템의 소형화가 가능하다. 본 연구에서는 전기자동차 레인지 익스텐더로 활용하기 위하여 초소형 가스터빈, 자동차용 알터네이터, 배터리를 사용한 초소형 가스터빈 파워팩 실험장치를 개발하고, 무부하 및 부하 조건에서 동력전달 기어비 및 알터네이터 전기부하에 따른 운전 특성 및 발전 성능을 측정하였다. 실험 결과, 부하 변화에 따른 발전 성능의 변화는 없었으며, 코어터빈 속도가 150 krpm 일 때 최대 전기적 출력은 0.8 kW 로 측정되었다. 또한, 동력축의 3:1 감속을 통해 전기적 출력은 1.5 kW 로 88% 증가하였다. 따라서, 본 연구의 초소형 가스터빈 파워팩은 배터리 부하변동에 대해 안정적인 전력생산이 가능하며, 전기자동차용 레인지 익스텐더로 적용가능함을 확인하였다.

• Tribology and Lubricants
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• 제33권2호
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• pp.65-70
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• 2017

In vertical hydro/hydraulic power turbine-generator applications, traditionally, cylindrical turbine guide bearings (TGBs) are widely used to provide turbine runner shafts with smooth rotation guides and supports. All existing cylindrical TGBs with simple plain pads have drawbacks such as having no pressure generation and film stiffness at the no-load condition and in addition, at the low-load/low-eccentricity condition, having very low film stiffness values and lacking design credibility in the stiffness values themselves. In this paper, in order to fundamentally improve the low-load/low-eccentricity performance of conventional cylindrical TGBs and thus enhance their design-application availability and usefulness, we propose to introduce a rotation-directional leading-edge taper to each partitioned pad, i.e., a pad leading-edge taper. We perform a design analysis of lubrication performance on $4-Pad{\times}4-Row$ cylindrical TGBs to verify an engineering/technical usefulness of the proposed pad leading-edge taper. Analysis results show that by introducing the leading-edge taper to each pad of the cylindrical TGB one can expect a constant high average direct stiffness with a high degree of design credibility, regardless of load value, even at the low-load/low-eccentricity condition and also control the average direct stiffness value by exploring the taper height as a design parameter. Therefore, we conclude that the proposed pad leading-edge tapers are greatly effective in more accurately predicting and controlling rotordynamic characteristics of vertical hydro-power turbine-generator rotor-bearing systems to which cylindrical TGBs are applied.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1682-1685
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• 2004

Gas Turbine combustors for power plant can be reduced NOx emissions using lean premixed combustion technology. But the combustors are likely to occur combustion oscillations which damage operation reliability and mechanical life of the gas turbines. In this paper, characterizations of oscillation in a gas turbine combustor for power plant are presented. Combustion dynamics occur $1{\sim}1.5$ psi in amplitude with low frequency less than 140Hz during normal operation. An abnormal high level dynamics, 2.0 psi amplitude occur at 125 Hz frequency. Abnormal combustion oscillation is reduced by modulation of fuel supply valve control schedule.

• 조명전기설비학회논문지
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• 제25권4호
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• pp.71-78
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• 2011

This paper contains the selection of operation parameters for protection and control of steam turbine in a Korea Standard Type Nuclear Power Plant. The safety of nuclear reactor must be ensured which generates nuclear energy and produces steam. Also, the safety of turbine, which consume the nuclear energy as a core machine, must be ensured. For the purpose of this, we describe how the operating parameters were selected, reviewed, implemented into the operator console and finally put into actual operation of the system.

• 전기학회논문지
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• 제58권6호
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• pp.1123-1129
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• 2009

The main goal of this paper is to simulate a Doubly-Fed Induction Generator (DFIG), which is similar to a real system. Wind velocity data is applied to a 2D Lookup table as a speed reference for a turbine model. A real electric machine's parameters are put in the simulator to get some results of the real system. The Matlab have been generally used to simulate DFIG, but it has some differences from the real system and is difficult to implement. A Simplorer simulator, however, simplifies DFIG simulation. The turbine is directly connected with the DFIG to be close to the real system. The machine's rotor is excited and controlled by the discrete carrier modulated matrix converter. It is possible to retrieve important information, like a generated power and wind quality etc., from the simulator without a huge wind turbine.

• Journal of Mechanical Science and Technology
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• 제14권11호
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• pp.1296-1304
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• 2000

A program of steady-state and transient performance analysis for a 200kW-class small turboshaft engine with free power turbine was developed. An existing turbojet engine was used for the gas generator of the developed turboshaft engine, which was modified to satisfy performance requirements of this turboshaft engine. To verify the accuracy of steady-state performance program for this engine: the program was applied to the gas turbine test unit of the same type, and the analysis results were compared with experimental results. The developed transient performance analysis program using the CMF (Constant Mass Flow) method was utilized to analyze the cases of step increase and ramp increase of the fuel.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.375-381
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• 1999

In this study, turbine speed control algorithm is studied for Buk-Jeju steam turbine power plant and also digital governor system is designed for speed control of steam turbine in power plant. By using duplex I/O module, triplex CPU module, 2 out of 3 voting algorithm and adding self diagnostic ability, the reliability of the designed digital governor system can be acquired satisfactorily. Designed and manufactured digital governor system is implemented in a pilot steam turbine plant of 0.3kw output power Installed in Korea Maritime University. After a series of experiment the reliability and availability is confirmed and also stable operation is achieved.

• 한국유체기계학회 논문집
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• 제8권5호
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• pp.13-21
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• 2005

This study aims to analyze operating performance of a micro gas turbine with the aid of detailed measurements of various system parameters. In addition to embedded measurements, parameters such as exhaust temperatures, engine inlet temperatures and fuel flow rates are measured. Variations in measured data and estimated performance parameters are analyzed. Those data are processed to calculate losses along the power transmission line and the net gas turbine performance (power and efficiency based on the gas turbine shaft end) is isolated from the overall system performance. A method to estimate characteristic parameters such as component efficiencies, based on the comparison between measured and predicted performance data, is suggested and exemplified for the full load condition.

• 한국유체기계학회 논문집
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• 제14권2호
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• pp.35-40
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• 2011

This study analyzed the influence of firing biogas on the performance and operation of a gas turbine combined heat and power (CHP) system. A reference CHP system designed with natural gas fuel was set up and off-design simulation was made to investigate the impact of firing biogas in the system. Changes in critical operating parameters such as compressor surge margin and turbine blade temperature caused by firing biogas were examined, and a couple of operating schemes to mitigate their changes were simulated. Part load operation of the biogas-fired system was compared with that of natural-gas fired system, and it was found that as long as the two system produce the same electric power output, they exhibit nearly the same heat recovery.

• International Journal of Fluid Machinery and Systems
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• 제9권3호
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• pp.237-244
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• 2016

An unsteady three-dimensional simulation based on Reynolds time-averaged governing equation and RNG $k-{\varepsilon}$ turbulence model, was presented for pump-as-turbine, the pressure fluctuation characteristic of hydraulic turbine with guide vane was obtained. The results show that the time domains of pressure fluctuation in volute change periodically and have identical cycles. In volute tongue and inlet pressure fluctuations are light, while in dynamic and static coupling interface pressure fluctuations are serious; In impeller blade region the pressure fluctuation of pressure surface are lighter than that of suction surface. The dominant frequencies of pressure fluctuation concentrate in low frequency region, and concentrate within 2 times of the blade passing frequency.